The recent dramatic advances in the field of multimedia systems has made practicable the development of an Intelligent Tutoring Multimedia (ITM): In these systems are present hypertextual structures that belong to the class of hypermedia systems. ITM development involves the definition of a suitable navigation model in addition to the other modules of an Intelligent Tutoring System (ITS), i.e. Database module, User module, Interface module, Teaching module. The navigation module receives as inputs the state of the system and the user's current assessment and tries to optimize the fruition of the knowledge base. Moreover, this module is responsible for managing the effects of disorientation and cognitive overhead. In this paper we deal essentially with four topics: (i) to define a fuzzy-based user model able to manage adequately the user's cognitive state, the orientation, and the cognitive overhead; (ii) to introduce fuzzy tools within the navigation module in order to carry out moves on the grounds of meaningful data; (iii) to define a set of functions that can dynamically infer new states concerning user's interests; (iv) to classify the hypermedia actions according to their semantics. (C) 1998 Elsevier Science Inc. All rights reserved.
